For many years retention pins have been used for the treatment of broken and undermined teeth, in particular for fixing restorations, for example corners.
Such pins generally have small dimensions, for example a diameter of 0.8 mm and a length of 4-6 mm. Inserting such pins into bores presents problems in handling. In the course of time different instruments, devices and methods have been developed for such insertion. For example, U.S. Pat. No. 4,155,162 discloses a dental anchor magazine in which a single anchor is housed and in which the magazine and anchor include a device for pushing and rotating the anchor whilst inserting it into the tooth. However, with the device described in that patent, a substantial part of the post has to be thrown away after the anchor part has been fixed and broken at a reduced thickness portion of it. Thus the whole magazine is expended for the use of only the part of the post which is used as a retention pin, the rest being wasted. Furthermore, at least the part being inserted is threaded and the other end, which remains, has a right angled manipulating section.
In another insertion method, taught in U.S. Pat. No. 3,928,915, the pins are not screwed in but cemented, for example with a cement for anchoring pins in a tooth for restorations, such as a cement on the base of cyanoacrylate which hardens instantly. Using the teachings of this patent, it is possible to insert several pins at the same time. For procuring a better anchoring, the pins are structured. The fast fixing of the pins allows the use of a strip comprising several pins which are connected together by portions of reduced thickness. However, for handling such strips and inserting pins into a bore in a tooth it is still necessary to use tweezers or similar tools.